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View Full Version : WWII Radio Equipment - How On Earth Did They Do This?



Monson74
09-08-2004, 03:20 AM
Being a guitarist & owner of an all tube amplifier I know how delicate & fragile valve technology is compared to solid-state (transistor) equipment. Any sound equipment including radios must have some sort of amplification circuit in order to work but how can you have a tube amplifier installed in an aircraft designed for combat & rough landings & not break it? How reliable were the radios back then?

S!

Monson


"The Zerst├┬Ârers will form an offensive circle." - G├┬Âring

Monson74
09-08-2004, 03:20 AM
Being a guitarist & owner of an all tube amplifier I know how delicate & fragile valve technology is compared to solid-state (transistor) equipment. Any sound equipment including radios must have some sort of amplification circuit in order to work but how can you have a tube amplifier installed in an aircraft designed for combat & rough landings & not break it? How reliable were the radios back then?

S!

Monson


"The Zerst├┬Ârers will form an offensive circle." - G├┬Âring

Dammerung
09-08-2004, 04:02 AM
They were so reliable that pilots left them behind because they weighed so much. /sarcasm

Oh, there are no fighter pilots down in hell...
Oh, there are no fighter pilots down in hell...
The whole damn place is full of queers, navigators, and bombadiers...
Oh, there are no fighter pilots down in hell...

Tully__
09-08-2004, 04:04 AM
The early HF (operating frequency less then 30MHz) were really dodgy. Around 1940 VHF radios began to appear (30-300MHz) with much improved but still dodgy reliability (they worked 80% of the time instead of 40%). The disadvantage of VHF is it gave much less reliable "over the horizon" communication, which is the reason that bombers continued to be equipped with HF gear for long range missions.

By the end of the war UHF was coming into use (300-3000MHz, though in those days not much more than 300MHz) with reliability improved even more.

The advantages of the higher freqency gear is a consequence of them using more compact valves (among other thing). Smaller valves are less prone to vibration, place less strain on the internal structure of the radio in high G manouvers and take up less space. They are also more tolerant of small changes in transmitting and receiving frequencies (particularly after the introduction of phase or frequency modulation in place of the simpler but more prone to noise amplitude modulation).

A further difference between WW2 radio gear and your sound gear is that many of the valves were metal or ceramic rather than glass. More expensive, but stronger. Only the final transmitter stages had to be able to shed lots of heat, most of the components were only dealing with power levels less than 1 watt.

And finally, with the introduction of magnetrons for the higher freqency signal generation (a consequence of radar research) the final amplification stages for the transmitters became much more reliable.

As I'm no radio techinician I'm sure I've missed some details, but that should give you the general idea.

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Salut
Tully

PBNA-Boosher
09-08-2004, 05:47 AM
A Russian ace interview was posted here a while ago back, it had some talk based on the radios....

Boosher
_____________________________
"So do all who live to see such times, but that is not for them to decide. All you have to decide is what to do with the time that is given to you..."
-Gandalf

Monson74
09-08-2004, 08:12 AM
Outstanding reply Tully! So the valves were simply made from a harder material - my guess would have been some sort of suspension or a shake-absorbing container - but you know about this I see. Interesting. http://ubbxforums.ubi.com/images/smiley/16x16_smiley-happy.gif

S!

Monson


"The Zerst├┬Ârers will form an offensive circle." - G├┬Âring

horseback
09-08-2004, 04:59 PM
Soviet AF was using tube/valve technology well into the 80s. My own experience in the USN during the '70s involved a lot of tube technology (for example, our standard surface search radar was the SPS-10, originally designed in the late 40s), and generally, the tubes were standard glass tubes anchored with spring or screwed down retainers/clips, The electronic units themselves were usually mounted on springs to limit shock/shaking damage. Broken tubes were rare, in my experience.

As long as the tubes/valves stayed in their plugs, they worked quite reliably, although they took up a lot of space and generated a lot of heat.

The items that failed most often were capacitors (condensors) and resistors. These failures were most easily detected by their smell, and rarely engaged in what we called the Viking Funeral Syndrome that seemed to characterize solid state component failures ("If I'm gonna die, I'm taking the rest of you with me, so that you can be my slaves in Valhalla.").

cheers

horseback

"Here's your new Mustangs, boys. You can learn to fly'em on the way to the target. Cheers!" -LTCOL Don Blakeslee, 4th FG CO, February 27th, 1944

WTE_Galway
09-08-2004, 05:05 PM
of course valve technology is also highly resistant to EMP damage ..

supposedly one of the reasons the soviets delayed the move to semiconductor technology in front line aircraft

newer is not always better

horseback
09-08-2004, 10:06 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by WTE_Galway:
of course valve technology is also highly resistant to EMP damage ..

supposedly one of the reasons the soviets delayed the move to semiconductor technology in front line aircraft

newer is not always better<HR></BLOCKQUOTE>

Yeah, that's so much easier than admitting you can't get your workers to maintain a decent clean room environment. We supposedly have some shielding from EMP, but who wants to test it?

cheers

horseback

"Here's your new Mustangs, boys. You can learn to fly'em on the way to the target. Cheers!" -LTCOL Don Blakeslee, 4th FG CO, February 27th, 1944

lil_labbit
09-08-2004, 10:32 PM
your head is more fragile than any tube Monson http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif

believe me http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif

I designed & build a class A amp (DC coupled) http://ubbxforums.ubi.com/infopop/emoticons/icon_biggrin.gif hehe yep I know they say it can't be done lol :P I did ! It's Ultra-linear too hehehe http://ubbxforums.ubi.com/infopop/emoticons/icon_biggrin.gif

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lil_labbit
09-08-2004, 10:38 PM
Anda... an atomic bomb (any realy) needs a real fast switch ...

now that's mostly a tube called a "krytron" - its a piece of radio active material in a tube http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif - the cloud of atoms/electrons to react is there - no warming - no whatever - just bang switch...
on/off lol
or off/on realy ...

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Question: Did you back-up your files?
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BaldieJr
09-08-2004, 11:35 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by horseback:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by WTE_Galway:
of course valve technology is also highly resistant to EMP damage ..

supposedly one of the reasons the soviets delayed the move to semiconductor technology in front line aircraft

newer is not always better<HR></BLOCKQUOTE>

Yeah, that's so much easier than admitting you can't get your workers to maintain a decent clean room environment. We supposedly have some shielding from EMP, but who wants to test it?

cheers

horseback

"Here's your new Mustangs, boys. You can learn to fly'em on the way to the target. Cheers!" -LTCOL Don Blakeslee, 4th FG CO, February 27th, 1944<HR></BLOCKQUOTE>

Thank you.

I get so sick of the emp protection rumor. Its not even true. If the equipment could be made out of only tubes, with no xformers, inductors, or rectifiers, I might think it plausible.

I wanna know what labbit was doing making class A's with dc coupling. Sounds like one of those renegade broadcasters... Radio Free Sturmovik?

I built a few myself back when I was a radio head. I had a constant supply of HF triodes of the 24kv variety http://ubbxforums.ubi.com/images/smiley/16x16_smiley-wink.gif

Oh it was nasty. I popped the neighbors TV set (unrepaiable) from 100 meters and left burn marks on my antennae. http://ubbxforums.ubi.com/images/smiley/16x16_smiley-very-happy.gif

The last "biggun" I had caused me to rewire half my home.

If you think AEP is addictive, try radio sometime!

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Hey ya'll prepare yourselves
for the rubberband man!</A>
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http://www.fighterjerks.com

Tully__
09-09-2004, 02:15 AM
So Baldie, it sounds like you know more about it than I do, please correct any errrors in my explanation. I haven't looked at RF technical specs for about 15 years so not only did I not know that much to start with, I'm kinda rusty http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif.

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Salut
Tully

JG52MadAdler
09-09-2004, 02:40 AM
rgrt
My Dad was a radio/Radar man on a PB4Y in England.
He never told me of having any problems with
the equipment. Tubes can be tough cookies.
He later worked as a radio repairman for the
Boston Fire Dept. He retired when they went digital. He loved the old tube stuff.

~S~


Fliege mit Mut, Fliege mit Ehre

BaldieJr
09-09-2004, 06:58 AM
You covered it spot-on Tully. Looks like there might be some 'electronics tech' left in you after all these years of computing http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

Internet killed the radio tech.

<A HREF="http://officemax.secureportal.com/" TARGET=_blank>
Hey ya'll prepare yourselves
for the rubberband man!</A>
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http://www.fighterjerks.com

Duncan_Doenitz
09-09-2004, 07:41 AM
I'm no radiohead, just an old guy who remembers the old tube type radios. I'm thinking of the old car radios, which of course were meant only to receive signals, not trnasmit. I know there also are differences in the radios depending on frequencies used and range of use, but some of the reliability issues must still have been similar.

Remember, the cars of the WWII era had radios in them, too, and they were fairly reliable and easy to fix. And they took a lot of abuse, too... roads were not the freeways we drive today.

In the old cars, radios were considered more of a luxury item and not a necessity, so us younger guys, buying an old used car and needing our tunes could go to a salvage yard where they would have shelves of used radios, many of them salvaged from cars that had been in collisions.

In fact, I've got a restored '39 Chev Master Deluxe, their top of the line model with options like knee action front suspension and city/country horns and the car was originally sold without a radio or a heater or defroster or turn signals. Its radio is salvaged from another car, and the heater, turn signals, and defroster (a fat little fan with leather blades) are aftermarket add ons.

Dunc

[This message was edited by Duncan_Doenitz on Thu September 09 2004 at 06:50 AM.]

Heavy_Weather
09-09-2004, 01:47 PM
some A/C carried extra tubes in a holder right next to the cockpit, assuming they would incounter these issues.

"To fly a combat mission is not a trip under the moon. Every attack, every bombing is a dance with death."
- Serafima Amsova-Taranenko: Noggle, Ann (1994): A Dance with Death.

Aaron_GT
09-09-2004, 03:07 PM
A good 1960s point-to-point
soldered 1960s amp head is less fragile then you imagine. A manufacturer in the 1960s demonsrated this by throwing one out of a window down a 15 foot drop on to concrete. New valves and it was fine. (I have a 1972 amp of the same type but I am not going to test this!)

Radios fir aircraft need less raw power than a 60W guitar amp which means less beefy transformers which are the things most likely to work loose.

The valves themselves can be suspended and cushioned.